Electronic Device for Pathogen Detection

• US 20130105317A1
• Filed: 10/31/2012
• Published: 05/02/2013
• Est. Priority Date: 10/31/2011
• Status: Active Grant

• Current Assignee: Fluid-Screen Inc.
• Original Assignee: Fluid-Screen Inc.
• Inventors: Reed, Mark A., Weber, Monika, Lo, Siu Lung, Montanaro Ochoa, Hazael Fabrizio, Yerino, Christopher Daniel
• Granted Patent: US 9,120,105 B2
• Time in Patent Office: Days
• US Class Current: 204/451
• CPC Class Codes: B01L 2300/0874 Three dimensional network
• CPC Class Codes: B01L 2400/0406 capillary forces
• CPC Class Codes: B01L 2400/0424 Dielectrophoretic forces
• CPC Class Codes: B01L 2400/0487 fluid pressure, pneumatics
• CPC Class Codes: B01L 3/502753 characterised by bulk separation arrangements on lab-on-a-chip devices, e.g. for filtration or centrifugation separation in general B01D; microapparatus for analysis using electrophoresis G01N27/44791; sample preparation G01N1/28
• CPC Class Codes: B03C 2201/26 for use in medical applications
• CPC Class Codes: B03C 5/005 Dielectrophoresis, i.e. dielectric particles migrating towards the region of highest field strength B03C5/02 takes precedence; electrophoresis B01D57/02
• CPC Class Codes: B03C 5/024 using high-gradient differential dielectric separation, i.e. using a dielectric matrix polarised by an external field
• CPC Class Codes: G01N 27/4145 specially adapted for biomolecules, e.g. gate electrode with immobilised receptors
• CPC Class Codes: G01N 33/487 of liquid biological material

Abstract

An apparatus and method for separating an analyte from a test sample, such as bacteria from blood components, based on their dielectric properties, localizing or condensing the analyte, flushing substantially all remaining waste products from the test sample, and detecting low concentrations of the analyte. Species movement is caused by a module array imparting opposing dielectrophoretic forces. The module array includes a plurality of microfluidic channels with connecting microfluidic waste channels for directing undesired material away from the analyte. An electric field is applied causing a positive dielectrophoretic force to the analyte to capture the analyte. The Clausius-Mossotti factor of the analyte is changed by flushing the analyte with a reference solution, which causes a negative dielectrophoretic force to facilitate release of the analyte. A field effect nanowire or nanoribbon sensor detects the analyte after capture.

Claims

1. An apparatus for pathogen detection comprising:

a first chamber for storing a test sample including product to be analyzed and microscaled components to be separated from said product to be analyzed;

a second chamber for storing a reference solution;

a pump for pumping said test sample and said reference solution;

a microfluidic separator separating said product to be analyzed from said microscaled components, said microfluidic separator including a plurality of microfluidic channels, each microfluidic channel including;

electrodes for producing a dielectrophoretic force on said test sample when said test sample is pumped through each of said microfluidic channels to perform a dielectrophoresis-based separation; and

channels for transporting said microscaled components away from said product to be analyzed;

a third chamber for storing said microscaled components when separated from said product to be analyzed by said plurality of microfluidic channels;

a condenser for capturing said product to be analyzed once said product has passed through said microfluidic channels and is substantially separated from said microscaled components; and

said sensor for detecting said product to be analyzed.

2. The apparatus of claim 1 wherein said plurality of microfluidic channels are assembled in an array, each microfluidic channel having electrodes on internal walls for delivering said dielectrophoretic force to said test sample traversing through said microfluidic channel.

3. The apparatus of claim 2 wherein said electrodes are located on opposing or adjacent internal walls of said microfluidic channels.

4. The apparatus of claim 2 wherein said microfluidic channels comprise a plurality of plates having an electrode configuration, and a plurality of internal channel structures patterned with electrodes, such that each microfluidic channel represents an elongated pathway for said test sample capable of providing a dielectrophoretic force to said test sample as said test sample traverses said microfluidic channel.

5. The apparatus of claim 4 wherein said plurality of plates and said plurality of internal channel structures are combined to form said array of microfluidic channels.

6. The apparatus of claim 1 including a collecting electrode to attract said product to be analyzed at an inlet of said sensor.

7. The apparatus of claim 1 wherein said sensor includes a nanowire sensor, nanoribbon sensor, or ion sensitive field effect transistor, and is capable of applying a confining dielectrophoretic force, trapping said product to be analyzed.

8. The apparatus of claim 6 wherein said sensor includes an array of field effect transistor biosensors.

9. The apparatus of claim 7 wherein said sensor surface includes geometry to enhance capture of said product to be analyzed.

10. The apparatus of claim 1 wherein said pump comprises a micro-pump operating in tandem with micro-valves to achieve a fully automated pathogen detection filtration system capable of miniaturization to a chip-scale design.

11. The apparatus of claim 1 including a microfluidic transport module for transporting said product to be analyzed to a location in the vicinity of a sensor.

12. An apparatus for pathogen detection comprising:

a microfluidic assembly including a plurality of microfluidic channels forming an array, each of said microfluidic channels including;

electrodes for establishing dielectrophoretic forces on a test sample separating said portions of said test sample into an analyte and a waste product; and

adjacent microchannels for receiving said waste product attracted by a dielectrophoretic force, removing said waste product from said analyte;

a condenser including an electrode for localizing said analyte for sensing; and

a sensor for detecting said analyte.

13. The apparatus of claim 12 wherein said microfluidic channels comprise a plurality of plates having an electrode configuration, and a plurality of internal channel structures patterned with an electrode configuration, such that each microfluidic channel represents a pathway for said test sample capable of providing a dielectrophoretic force to said test sample as said test sample traverses said microfluidic channel.

14. The apparatus of claim 13 wherein said plurality of plates and said plurality of internal channel structures are combined to form said array of microfluidic channels.

15. A method of pathogen detection comprising:

providing a test sample including an analyte together with a waste product;

providing at least one reference solution;

transporting said test sample through a plurality of microfluidic channels;

generating dielectrophoretic forces on said test sample as said test sample is transported through said plurality of microfluidic channels;

separating said waste product from said analyte by said dielectrophoretic forces;

directing said waste product away from said analyte;

directing said analyte to a condensing area;

condensing said analyte in a localized area;

flushing said analyte with said reference solution to remove substantially all of remaining waste product from said condensed analyte;

detecting low amounts of analyte using a microfluidic sensor.

16. The method of claim 15 including dielectrophoretic manipulation of said analyte to said microfluidic sensor to overcome a diffusion limitation and enable analyte contact with said microfluidic sensor surface for detection.

17. The method of claim 15 including introducing a pharmaceutical or other substance which pierces membranes of an alive analyte component in said reference solution at a predetermined frequency, but not membranes of other analyte components or dead analyte components, and differentiating said alive component from other analyte components and dead analyte components through dielectrophoretic forces.

18. The method of claim 15 including using the change of a Clausius-Mossotti factor, CM(ω

), upon a change of a medium permittivity, ∈

_m, for analyte capture and release.

19. The method of claim 18 wherein said capture includes:

applying an electric field causing a first dielectrophoretic force to said analyte to facilitate analyte capture;

changing said Clausius-Mossotti factor by said flushing; and

causing a second dielectrophoretic force under said electric field acting on said analyte with said changed Clausius-Mossotti factor to facilitate release of said analyte.

20. The method of claim 19 including adjusting pH or conductivity of said test sample for control of voltage and frequency dependence for said Clausius-Mossotti factor cross-over frequency.

21. The method of claim 19 including inducing change of said Clausius-Mossotti factor cross-over frequency for said analyte by adding or mixing an additional fluid.

22. The method of claim 19 including tuning said electric field to said analyte such that said analyte is isolated by said dielectrophoretic force.

23. The method of claim 15 wherein said step of separating said waste product from said analyte includes:

providing a microfluidic assembly including a plurality of microfluidic channels forming an array, each of said microfluidic channels including;

electrodes for establishing dielectrophoretic forces on said test sample separating said portions of said test sample into said analyte and said waste product; and

adjacent microchannels for receiving said waste product attracted by a dielectrophoretic force, removing said waste product from said analyte;

transporting said analyte to said condenser area; and

localizing said analyte at said condenser area by a condenser electrode.

24. The method of claim 15 wherein said step of detecting low amounts of analyte using a microfluidic sensor includes using an electric field at predetermined flow conditions, to immobilize said analyte on a nanowire or nanoribbon sensor surface.

25. The method of claim 15 including superpositioning or tuning of frequency components, waveform shapes, and waveform tunings, or any combination thereof, to maximize separation, differentiation, capture, or release of said analyte.

26. The method of claim 15 wherein said dielectrophoretic forces include at least two opposing forces.

27. A filtration system for pathogen detection comprising:

microchannels for fluid transport;

a dielectrophoretic separator for separating said fluid into constituent components;

a dielectrophoretic condenser for condensing at least one constituent component of said fluid;

a dielectrophoretic transport module; and

a field effect based sensor, nanowire sensor, nanoribbon sensor, or ion sensitive field effect transistor, or any combination thereof, for detecting said at least one constituent component of said fluid.

28. The filtration system of claim 27 wherein said dielectrophoretic separator includes a parallel multichannel structure having a plurality of microfluidic channels in multiple stacked layers, and branched with waste channels.